Art of reproducing sound vibrations



H. K. SANDELL.

ART or REPRODUCING souuo VIBRATIONS.

APPLICATION LED AFR. I919- Patented Sept. 20,1921.

2 SHEETS-SHEET I.

UNITED STATES PATENT OFFICE.

HENRY K. SANDELL, OF CHICAGO, ILLINOIS, ASSIGNOR 'lO HERBERT S. MILL S, OF

CHICAGO,

ILLINOIS.

ART OF msrnonucms soum) vrnmrrrons.

' Chicago, in the county of Cook and State of Illinois, have invented a new and useful Improvement in the Art of Reproducing Sound Vibrations, of which the following is a specification. I

This'invention relates to-improvements in the art of recordingsound vibration, particularly as applied to the formation of such records in plastic materials for. the purpose of subsequent reproduction of the sound recorded. v

In processes for reproducing sound from recorded sound impressions on plastic material as now in common use, wherein a diaphragm is caused to vibrate through the intermediary of a stylus or other guiding means which are caused to follow the record or impression of the sound vibration in the plastic material, the amplitude of the recorded vibration is a material factor in determining the volume of sound emitted by the reproducing mechanism. In many instances the recorded vibrations are of so small, an amplitude as to result in a very small volume of sound, which in many cases is almost inaudible. Furthermore, when the recorded vibrations are of small amplitude the relative proportions of mechanical imperfections, scratches, etc.,, is comparatively great, and there is a correspondingly great disturbance of the sound emitted by the reproducing mechanism. By proportionally increasing theamplitude of the vibration as recorded, the disturbances and noises due to such mechanical imperfection, scratches and other causes are proportionally reduced at the same time.

Among the objects of my invention are to.

provide a process whereby the amplitude of sound vibrations, or their longitudinal proportions, as recorded particularly in plastic materials, may be varied in accordance with lize a primary record of suitable material,

wherein sound vibrations are recorded by any known means, for example, by means of a u t g 90.1 wa ed re a flexible 39.-

Specification of Letters ratent. P t nt d S t 20, '1921 Application filed April 4, I

1919. Serial No. 287,420.

phragm, which is vibrated by the sound waves to be recorded. From the primary record or from a suitable plastic or galvanoplastic copy thereof, I effect the reproduci tion of the recorded vibrations, varying the amplitude and longitudinal proportions thereof in a predetermined manner. Suitable means for carrying out the present invention are illustrated in the accompanying drawings, in which-- I Figure 1 is a plan view of the device illustrated; 7

Fig. 2 is a section view on line 2 of Fig. 1

F ig. 3 is a sectional view on a horizontal plane, illustrating the driving mechanism for the device;

Fig. 4 is a sectional view on line 44 of Fig. 3; I

Fig. 5 is a sectional view on line 55 of Fig. 1;

Fig. 7 is a view illustrating on a greatly exaggerated scale a typical voice wave record; Fig. 8 is a similar view of the record produced on increasing proportionality throughout the amplitude of the vibration of the curve of Fig.7, and

Fig. 9 is a view illustrating the wave record produced by increasing the amplitude and the longitudinal proportions of the same wave as shown in Fig. 7

As illustrated in the embodiment of the apparatus ofmy invention shown in the accompanying drawings, the driving mechanism is contained in a housing 10 which serves as a support for the entire device.

.The device asillustrated comprises essentially two supports, one of. which is intended for the reception of the primary record con-- taining the impression of sound waves and the other for the reception of a similarly shaped record upon which the corresponding impressions are to be produced with the proportions of the sound waves varied in accordance with the desires of the operator.

In the preferred form of construction of the device for use with disk records, as illustrated, each of these supports consists of a flat horizontal table 11, mounted on a rotatable spindle 12, which is supported'in vertical position by a bearing 13 and a thrust bearing 14, the said bearings being preferably spaced from each other and formed in 9 Qni ary casting.

is a sectionalview on line 66 of mounted upon spindles 12, 12 of the; record support in order to rotate the same. The

worm-wheels 15, 15 are engaged by the worms 16, 16, mounted on the rotatable driving shaft 17, which lies in a substantially horizontal position. The drive shaft '17 is mounted in slidable bearing blocks 18, which are movable in the slides or slots formed in the spaced' standards 19. Bolts 20 may be provided to prevent the bearing'blocks 18 leaving the slot. The worms 16 on'the drive shaft 17 are held in firm engagement with the "worm-wheels 15, preferably by spring pressure. In the embodiment illustrated collars 21, "21 are mounted" on the drive shaft 17, the latter being rotatable in said collars, and spiral springs 22, 22 are-attached to said collars in such manner as to draw the entire driveshaft toward the wormwheels and thereby cause close engagement of the two portions of the worm-gear. The

drive shaft 17 is provided with a suitable drivinggear, such as the pulley 23. f

It is readily apparent that with the above driving mechanism, by using identical wormwheels 15, 15, a synchronous drive of the two supports '11, 11 maybe obtained. By replacing either worm-wheel 15' by another worm-wheel having a greater or less diameter, the speed of the rotation of the corresponding' support will be accordingly decreased or increased. The arrangement of the drive shaft 17 in slidable blocks, as illustra'ted, the elements of the worm-gear being held in firm engagement by spring pressure,

, insures accurate drive of the support spindles 12, regardless of the size of the worm-wheel 15 the present embodiment of my process, I have illustrated the primary record of the sound waves as a disk record upon which sound waves are recorded laterally either as depressions or elevations upon the surface thereof. Such a record is mounted upon one of the support tables of the device as illustrated in the drawings- To produce the sound waves of the desired amplitude or having the desired modification in the rate of longitudinal movement, a blank record,

preferably of similar form, capable of receiving an impression, ismounted upon the other supporting table 11. By the use of identical gear wheels 15, 15,'the two supports may be given an identical rate of rotation, with the result that the longitudinal proportions of the recorded. sound Waves To effect the reproduc'on of the sound waves, I utilize means'whereby the'l'novement of a guide member controlled by the recorded impressions on the primary or masticularly in Figs. 1, 2 and 6, may suitably consist of a lever of the first class provided with aguide member at one end and a cutting tool at the other, said lever being adj ustably fulcrumed upon an axis which, in the case of lateralsound impressions, is in a vertical position. The lever may consist, as illustrated, of a suitably eurved'metal bar 26 provided approximately centrally with a slot 27 extendinglongitudinally of the lever and-further provided at *one end with a holder 28 for the guiding means,

as a stylus which will follow the impres- The stylus or guide member-29 is removably retained inthe holder 28 by means of set screw 30. At the other end of the lever bar 26 is attached a continuation thereof in 'which is illustrated in the present instance 'sions of sound waves in master-record 24.,

the form of the metal bar 31, the point of attachment to the lever'bar 27 being at some distance from its end, as indicated at 32. -At the end of the lever bar '27 a screw 33 is provided, which engages the resilient -con- 4 tinuationn1ember'31 and-forces it downwardly "to "a greater or less extent. The

member 31. is provided at its end with a holder 34 which 'removably retains a suitable cutting: member 35, for exampleby means of set screw 36. The cuttingmember engages the blank record 25. Thelever members 26 and 31- are preferably- ;formed of resilient metal, and the relative resiliency of these parts may be increased or decreased by means of the screw 33.'- Bythis means-ac "curateeontaet 'of' the cu'tti'ng and" guiding tools may be assured. 'The lever is 111: crumed upona short bearing or arbor 38,

j which is slidable within the slot 27 and may besecured in any desired position in said 'slot by means of the cooperating nuts 39,

39, of which, one is provided on each side of the lever bar '26. This arbor is rotatably mountedin pin bearings 40, 41, which are provided on theforks '42. The forks 42 form the termination of the arm 43, which arm is rotatably mounted on the stud 44 uponwhich is fitted the nut 47. The arm 43 may beheld in any desired position by 7 means of said screw and nut. The pin bearing 41 in the fork 42 may be suitably'threaded into position in order that it may be adjusted or moved to a sufficient distance from described) in reproducing sound impresfrom the cutting tool to the bearing is, forexample, twice that from the guiding tool to the bearing. It now the two records, 2l and 25 are rotated at equal speed, the guiding tool 29 following accurately the impressions in the master-record 24, the cutting tool 34 will form like impressions in the blank record 25, the lateral amplitude of the impressions formed being twice that of the original impressions and the longitudinal proportions of the impressions being unchanged. The results thus produced will be more clearly apparent from a consideration of Figs. 7 and 8, in which Fig. 7 illustrates the original impression of a voice curve, and Fig. 8 illustrates the resulting curve on multiplying th amplitude of the vibrations by two witho t altering the longitudinal proportions.

As a further illustration of the operation of the device, it may be assumed that the lever bearing is so adjusted that the ratio of its lever arms are as three to two. If

7 now, in reproducing the impressions formed on master record. 24:,the rate of speed of travel of the blank record 25 and the master record 2% are as two to one, the resulting impressions formed in the blank record 25 will have their amplitude unchanged, but the longitudinal proportions thereof will be twice those of the impressions of the master record 24. This is further illustrated by Fig. 9, which indicates the curves produced on reproducing the curve of Fig. 7 increasing the amplitude of vibration by half and doubling the rate of travel of the record. It isapparent that the record containing the curve of Fig. 9 must travel at twice the speed of the record containing the curve of Fig. ,7 or of Fig. 8 to produce sounds of the same pitch.

It is apparent that by the process and apparatus of the present invention sound impressions may be produced having any de sired relation in amplitude or in their longitudinal proportions to the sound impressions formed on the original or masterrecord. Wherever the longitudinal proportions of the recorded impressions are varied, the speed at which the record produced must be operated to reproduce the sound must be varied accordingly. It is furthermore possible by the present process and apparatus to vary either the amplitude of the vibrations or their longitudinal proportions or both simultaneously.

Although it has been indicated in the preceding description that the master-record employed is one inwhich the sound vibrations are recorded in the form of grooves,

it is obvious that I may utilize records or dies on which the vibrations are recorded as ridges, the guiding stylus then assuming a V-shaped form instead of the needle form illustrated. The master-record employed may be of plastic material or of metal, or of other suitable material. The blankrecord upon which the impressions are reproduced in the desired proportion may be of wax or other suitable plastic material capable of readily receivlng the impression, although it is not without the scope of my invention to use any well known means, such as paper, capable of receiving an impression and imprinting thereon with ink or other suitable material to utilize my process in magnifying the impressions on the master-record for inspection.

It is furthermore readily apparent that the construction of my device may be varied for the purpose of utilizing records in which the impressions are formed with the vibrations in a vertical plane, or for the use of cylindrical records in place of either the master-record or blank record illustrated, or both, without departing from the essence of the present invention.

Although I have described the process and apparatus of the present invention in certain specific forms and details, I do not intend the scope of the invention to be limited thereby, except in so far as such limitations are included in the appended claims.

I claim:

1. In apparatus for reproducing sound record grooves, means for rotatably supporting a blank and a master record, means for forming an impression in the moving blank, a resilient lever supporting said forming means and adapted to hold it in engagement with said blank, said lever having a variable pivot point, means for supporting said pivot point, guiding means attached to saidlever and adapted to be held by it in engagement with the moving master record, and means for varying the resilient thrust of said lever upon said forming and guiding means.

2. In apparatus for reproducing sound record grooves, means for rotatably supporting a blank and a master record, a pivoted lever, means for supporting said lever, guiding means adapted to engage the grooves of the master record, said guiding means being secured to and controlling the pivotal movements of said lever, a resilient bar attached to said lever and forming a continuation thereof, cutting means attached to said bar, and adapted to engage the moving blank, and means for increasing the resilient thrust of the bar.

HENRY K. SANDELL. 

